The prevalence of human T-lymphotropic type I virus (HTLV-I) among patients with sexually-transmitted diseases is studied in Russia. Primary screening of antibodies to HTLV-I in the sera was carried out by enzyme immunoassay with recombinant gag and env HTLV-I-specific antigens synthesized in Escherichia coli. For secondary screening, Serodia HTLV-I and Vironostika Microelisa System kits were used. None of the 1271 serum samples collected in the towns of Perm and Ekaterinburg was HTLV-I-positive. This indicates a lower, in comparison with other European countries, level of infection with this virus, at least in this region of Russia. Testing of sera from 79 HIV-infected patients revealed none infected with HTLV-I.